Sensing and Bio-Sensing Research (Dec 2021)
Multiplexed detection of aqueous Cd2+, Pb2+ and Cu2+ ions at mercury-on-graphene film modified electrode by DPASV
Abstract
With the ever-increasing influence of heavy metal ions in environmental pollution, it is highly desirable to develop facile, rapid, and low-cost methods for the multiplexed detection of heavy metal ions in aqueous media sensitively and quantitatively. In this study, we report a facile electrochemical method for the selective, quantitative and multiplexed detection of cadmium (Cd2+), lead (Pb2+), and copper (Cu2+) ions in aqueous media. In this method, a glassy carbon electrode (GCE) is modified first with reduced graphene oxide(rGO) microflaks followed by the controlled in situ electro-deposition of a very thin mercury film. The final working electrode, denoted as (Hg|rGO)film|GCE, was employed as the detector for reported multiplexed detection of multi-ions, taking advantages of the well-established polaragraphic principles. The rGO layer was known to be capable of significantly increasing the heterogeneous interface electron-transfer rate and therefore the detection sensitivity, while the highly dispersed over-potentials of heavy metal ions on mercury allowed the multiplexed detection of several heavy metals ions at different working potentials. The differential pulse anodic stripping voltammetry (DPASV) was employed as the detection mode to further boost up the detection sensitivity. Very good quantitative relationships were observed between the peak current in DPASV and the concentration of the ions being detected. The cross-interference in the multiplexed detection was found negligible. The limit of detections (LODs) of Cd2+, Pb2+, and Cu2+ ions in aqueous phase at the (Hg/rGO)film/GCE working electrode were found to be 0.17, 0.18 and 0.69 μg/L, respectively.
